Production of green shades on materials made of or containing cellulose esters or ethers



Patented Dec. 15," 1931 UNITED STATES PATENT OFFICE.

ALFRED DAVIDSON, OF IBLACKLEY, MANCHESTER, ENGLAND, ASSIGNOB '10 IMPERIAL CHEMICAL INDUSTRIES LIMITED, 01' LONDON, ENGLAND :enonuenon or GREEN snanns on MATERIALS we or on commute crmLUr-osn names on. mans No Brewing. Application filed Kay 23, 192i Serial No. 885,576, and in Great Britain June 9, 1928.

For the dyeing of cellulose esters or ethers compound, presumably ,N'-dimethylindigo, first described by Ettinger and Friedlander in Berichte der Deutsche Chemische' 1 gesellschaft, 1912, vol. 45, pages 20742076. I find that this compound may be applied directly in aqueous suspension in the presence or absenceof dispersing agents, protective colloids and the like. It may be pre- 20 pared in finely divided paste formandthe paste may be dried in the presence of suitable protective colloids to give a powder. which yields a dispersion when added to water. One method of applying my invention is 25 illustrated by the following example, in

which the parts are by weight.

Emample Fof'100 parts of acetate silk, a. dyebath is Cellulose esters or ethers dyed een shades and which contain incorporated t erewith N,N-dimethylindigo.

3. In the manufacture of dyed cellulose esters and ethers having green shades, the process which comprises applyin an aqueous suspension of N',N'-dimethylin 'go to such 50 cellulose esters'and ethers and thus directly I have now found that beautiful green shades may be obtained b the use of the dyeing such cellulose esters and ethers in green shades.

4. In the manutacture or (1 ed acetate silk have a bright green shade su stantially fast pension containing turkey red oil, and thus directly (1 eing said acetate silk in bright green sha es. 4

5. As a new product dyed cellulose esters and ethers having bright green shades, said dyed celluloseesters and ethers being dyed directly by N,N-dimethylindigo.

6. As a new product, dyed acetate silk having a bright green shade substantially fast to washing and soaping, said (1 ed acetate being dyed directly by Nfl -dimethyl- 1n 1 0:

7 In the manufacture ofdyed acetate silk having bright/green shades, the process which comprises immersing said acetate silk in a dye bath comprising an aqueous suspension of N,N'-dimethylindigo, said aqueous suspension contaimng turkey red oil and said dye bath being maintained at a temperature between 4050 C., keeping the acetate silk in said bath until the dye' is fixed on the acetate silk, and then removing the dyed acetate silk from the bath, rinsing and drying thus directly d eing the acetate silk in bright green sha es.

In testimony whereof I afiix my signature.

ALFRED DAVIDSON. 

